docs: def additionalAssignment(MobileAllocation_presence=0,
                           StartingTime_presence=0):
      """ADDITIONAL ASSIGNMENT Section 9.1.1"""
      # Mandatory
      a = TpPd(pd=0x6)
      b = MessageType(mesType=0x3B)  # 00111011
      c = ChannelDescription()
      packet = a / b / c
      # Not Mandatory
      if MobileAllocation_presence is 1:
          d = MobileAllocationHdr(ieiMA=0x72, eightBitMA=0x0)
          packet = packet / d
      if StartingTime_presence is 1:
          e = StartingTimeHdr(ieiST=0x7C, eightBitST=0x0)
          packet = packet / e
      return packet